The manufacturing methods and system in use today vary with the total quantity of identical parts that are to be produced. Where production quantities are sufficiently high, it is economically justifiable to provide for automatic machining on transfer lines. At the opposite end of the production quantity spectrum (where a relatively small number of identical items are required), the recently-developed numerically-controlled machines constitute a satisfactory means of semi-automatic manufacturing from an economic point of view. However, no efficient or adequate means are presently available to accommodate manufacturing in those situations where the production rate requirements fall between these extremes.
In the case of machining parts, the manufacturing systems that are used at the present time for providing for these interim production runs are those known as "way-type lines". Such production systems involve an assortment of general-purpose and/or special-purpose machine tools that are usually interconnected by roller conveyors. The production tooling is such that at each station the workpiece can be located and clamped; manpower is required to load and unload each machine tool and to move the workpiece from one machine tool to another. This system of manufacturing has several important deficiencies:
1. The initial investment is high in relation to the productive capacity that can be attained; this is particularly true in those cases where the maximum production rates do not result in good utilization of many of the work stations. PA1 2. The cost of the production tooling at each work station is high. PA1 4. A large amount of manual labor is required to operate the system. PA1 5. Floor space requirements are high, since separate lines normally are used to accommodate variations in configuration or machining operations that may be incompatible with those of other parts. PA1 1. Identify the workpieces approaching the module upstream of their arrival at the module; PA1 2. Search the tool logic unit memory bank for the location of the required tools for each part number approaching the station; PA1 3. Bring about the progressive removal of the required tools in the sequence that they will be used from the storage matrix into an inflowing queue line moving the tools toward the spindle; PA1 4. As tools are applied to the work, provide for their release from the spindle and return in a separate queue back towards the storage matrix; PA1 5. Remove tools from the return queue and place them back in the storage matrix.
3. The resulting system is very inflexible and requires a high investment to modify its manufacturing mission.
These and other difficulties experienced with the prior art teachings are overcome in a novel manner by the present invention.
It is, therefore, an object of the invention to provide a manufacturing system which makes possible the automatic manufacturing of parts now being produced with high labor content on way-type lines.
Another object of this invention is the provision of a manufacturing system that has the highest attainable process efficiency without sacrifice of system versatility. Also, the present invention provides a manufacturing system that makes use of work stations designed to give high process specialization and efficiency and further provides a means of automatically applying such stations to a wide variety of workpieces.
It is another object of the instant invention to provide a manufacturing system incorporating means for automatic operation of the entire system; this encompasses routing workpieces from station to station and providing automatic delivery to selected terminal points. The routing system is such that the sequence of movement from station to station may be random, meaning that automatic movement from any station to any other station in the system may occur selectively.
A still further object of the invention is the provision of a manufacturing system in which random order manufacturing can be accommodated, i.e., in which parts that differ widely from one another can be made in a random sequence. Automatic manufacturing of parts on a one-at-a-time basis can be accomplished without sacrifice of system efficiency.
It is a further object of the invention to provide a manufacturing system that can accommodate parts in random sequence, thus resulting in a major reduction in the investment required for production tooling.
It is a still further object of the present invention to provide a manufacturing system having a flexibility rendering it capable of producing parts in quantities of from one to many hundreds and thousands without adversely affecting the cost per part; this added flexibility makes it possible to attain an optimum relationship between varying production schedule requirements and the productive capacity of the manufacturing system.
Another object of the invention is the provision of a manufacturing system consisting of a variety of machine tools interconnected by a network of conveyors in such a manner that a mixture of different workpieces can be introduced into the system and subjected to a number of different machining operations and each machine tool is used to close to its optimum efficiency.
Another object of the invention is the provision of a manufacturing system making use of a network of conveyors joining a wide variety of work stations of varying capabilities, each workpiece cruising through the network to have a variety of operations such as machining, processing, assembly and inspection performed upon it, wherein the most efficient work stations are used when possible and the less efficient only when the more efficient are not available.
Another object of the invention is the provision of a manufacturing system capable of performing a variety of machining operations on a variety of different workpieces, means being provided to select a mixture of particular workpieces and associated production rates for a certain time period, using the various work stations in the system as efficiently as possible.
Another object of the invention is the provision of a manufacturing system providing for changing a cluster of tools where high hole-density appears in machine parts.
Another object of the invention is the provision of a manufacturing system providing for the changing of cluster heads carrying a plurality of tools at fixed center lines, the changing taking place at high speed thereby providing a highly efficient work station.
Another object of the invention is the provision of a manufacturing system using a predetermined arrangement of process specialized work stations usable on a variety of workpieces thus providing high system efficiency and versatility.
Another object of the invention is the provision of a manufacturing system incorporating automatic workpiece routing in a network of conveyors and numerically-controlled machine tools, wherein workpiece identification intelligence accompanies the workpiece during routing and control of the machining operations.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.